The present invention relates generally to box spring assemblies, and more particularly, to an improved box spring assembly in which a uniformly distributed resistance to bedding loads is obtained.
In box spring assemblies of the type such as is disclosed in U.S. Pat. No. 3,574,240, a horizontal mattress support framework is provided in a box spring assembly. The framework is defined by a plurality of spaced apart main wire springs, some of which extend longitudinally of the assembly and others of which extend transversely of the assembly. The wire springs are thus arranged in a criss-cross fashion forming rectangular spaces between adjacent longitudinally and transversely extending wire springs. The box spring assembly also includes a plurality of intermediate support springs, each of which includes a generally straight body portion and depending end portions. Each body portion of an intermediate support spring extends diagonally between adjacent springs thereby diagonally bisecting a rectangular space. It is desirable, however, to reduce the sizes of the other rectangular areas which are not bisected by the intermediate support springs so as to further increase the surface area of support for a mattress. It is also desirable to decrease the sizes of these rectangular areas in such a manner so as not to require a change in the basic construction of the box spring assembly.
It is the object of the present invention, therefore, to provide a grid unit which cooperates with the mattress support framework of the box spring assembly to provide improved and more uniformly distributed support for a mattress.